Pressurized fluid systems are often provided with emergency pressure control and relief capabilities to prevent the possibility of injury to humans and damage to equipment in the event of an over pressure situation. Such pressure control systems often use a pressure responsive member such as a buckling pin that mechanically fails when subjected to a large increase in fluid pressure, causing an axial force to buckle the pin. Failure of the pressure responsive member allows a valve assembly to operate to close so as to isolate the over pressure from downstream equipment, such as by shutting down the fluid flow.
There are also systems that operate to detect and abate underpressure conditions as a downstream line break. A rupture in a pressurized pipeline or similar network can result in a sudden drop in system pressure as the fluid escapes to the external environment. Thus it is often necessary to activate a valve assembly to isolate the fluid, such as a shutoff valve which halts further flow of the fluid, until the line break condition is remediated.
There is a continued need for improvements in the art to provide a pressure control system that operates when the pressure of a fluid falls outside a selected high or low operating range or a combination of both.